|Improved Photoabsorption in Thin Gallium Arsenide Solar Cells using Light Trapping Techniques|
|Julia D'Rozario, Steve Polly, Seth Hubbard, George Nelson
Rochester Institute of Technology, Rochester, NY, United States
In this work, increasing the photoabsorption in thin film single junction n-i-p gallium arsenide (GaAs) solar cells has been investigated by applying different light trapping structures. One focus has been to develop a random surface texture that varies in three dimensions to increase light scattering at the back of the cell. The random back surface reflector (BSR) was successfully applied to a 2.25 µm thick GaAs solar cell and resulted in a notable 92% increase in current between 873 nm to 950 nm when compared to the control GaAs solar cell on the substrate without a BSR. Simulations of flat reflectors with a dielectric distributed Bragg reflector (DBR) consisting of MgF2/ZnS show reflection greater than 99% between 750 nm and 900 nm. Combinations between the random BSR and DBR structures will be applied to GaAs solar cells on the sub-µm scale. The overall goal is to apply different light trapping structures in < 500 nm thick GaAs solar cells to achieve high output current as compared to the control GaAs solar cell on a substrate without a BSR.